From 7c99a333dade991a972037c753d2662c0117fe29 Mon Sep 17 00:00:00 2001
From: ctrlaltking <ryanking.az@gmail.com>
Date: Sun, 21 Jun 2026 23:21:08 -0700
Subject: [PATCH] fix(preview): flag unplayable media when previewing a
 standalone asset
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

previewAsset() created AVPlayerItem(url:) directly with no error
handling, so a corrupt or unsupported source file just left the
preview blank/frozen with no feedback. The timeline composition path
already detects this (offlineMediaRefs/unprocessableMediaRefs via
CompositionBuilder) and surfaces a "Couldn't Prepare Media" overlay —
this path never ran for assets previewed before being placed on the
timeline.

Probe the asset's tracks after swapping in the player item and mark
it unprocessable on failure, reusing the existing offline/unprocessable
UI instead of leaving a silent blank player.
---
 Sources/PalmierPro/Preview/VideoEngine.swift | 26 ++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/Sources/PalmierPro/Preview/VideoEngine.swift b/Sources/PalmierPro/Preview/VideoEngine.swift
index 39f5022de..a0c18de55 100644
--- a/Sources/PalmierPro/Preview/VideoEngine.swift
+++ b/Sources/PalmierPro/Preview/VideoEngine.swift
@@ -101,6 +101,32 @@ final class VideoEngine {
             return
         }
         replacePlayerItem(AVPlayerItem(url: asset.url), reason: "previewAsset")
+        verifyAssetPlayable(asset)
+    }
+
+    /// `AVPlayerItem(url:)` fails silently — a corrupt or unsupported file just
+    /// leaves the preview blank with no error. Probe the tracks so we can flag
+    /// it through the same offline/unprocessable UI the timeline path uses.
+    private func verifyAssetPlayable(_ asset: MediaAsset) {
+        let mediaType: AVMediaType = asset.type == .audio ? .audio : .video
+        let url = asset.url
+        let assetId = asset.id
+        Task { @MainActor [weak self] in
+            let hasTrack: Bool
+            do {
+                hasTrack = try await AVURLAsset(url: url).loadTracks(withMediaType: mediaType).first != nil
+            } catch {
+                hasTrack = false
+            }
+            guard let self, !Task.isCancelled, let editor = self.editor else { return }
+            guard case .mediaAsset(let activeId, _, _) = editor.activePreviewTab, activeId == assetId else { return }
+            if hasTrack {
+                editor.unprocessableMediaRefs.remove(assetId)
+            } else {
+                Log.preview.error("previewAsset: media unplayable assetId=\(assetId.prefix(8))")
+                editor.unprocessableMediaRefs.insert(assetId)
+            }
+        }
     }
 
     func activateTab(_ tab: PreviewTab) {